<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            background-color: blue;
        }
        #second{
            background-color: red;
        }
        .first{
            color: white;
        }

    </style>
</head>
<body>
    <!-- 标签可以使用的属性
     id  class style title 
     -->
    <div class="first" title="我是第一个div">块级元素</div>
    <div id="second">块级元素</div>
    <div>块级元素</div>
    <p class="first">段落标签</p>
</body>
</html>